The present invention relates generally to apparatus and methods for treating vascular conditions, and more specifically, to a balloon catheter having a configuration that improves the folding capability of a balloon after deflation of the balloon.
Atherosclerosis and other occlusive diseases are prevalent among a significant portion of the population. In such diseases, atherosclerotic plaque forms within the walls of the vessel and blocks or restricts blood flow through the vessel. Atherosclerosis commonly affects the coronary arteries, the aorta, the iliofemoral arteries and the carotid arteries. Several serious conditions may result from the restricted blood flow, such as ischemic events.
Various procedures are known for treating stenoses in the arterial vasculature, such as balloon angioplasty. During a balloon angioplasty procedure, a catheter having a deflated balloon attached thereto is inserted into a patient's vessel. In some cases, it is desirable to introduce the balloon in a configuration whereby the balloon is twisted or folded upon itself in order to reduce the radial profile of the balloon during delivery. Once positioned across a constricting lesion, the balloon is then inflated to widen the lumen to partially or fully restore patency to the vessel. After satisfactory widening of the stenosis has been achieved, the balloon is deflated. The catheter is then retracted and removed from the patient's vessel with the balloon in the deflated state.
An important problem that exists with the use of conventional angioplasty balloons is that they may not be reliably collapsed after deflation. For example, after the balloon is expanded to engage the vessel wall and then deflated, the balloon may obtain a flattened configuration, e.g., having two opposing regions that extend radially outward. In those cases, it may become difficult to withdraw the balloon from the patient's vessel. If an introducer sheath is used, the balloon may become caught within the sheath upon retraction and removal.
In view of the foregoing, there is a need for a balloon catheter that achieves a sufficiently collapsed radial profile in order to be removed after deflation. In particular, there is a need for an apparatus that promotes an orderly folding of the balloon upon itself, thereby achieving a reduced profile and reducing the likelihood that the balloon will become caught upon removal from the patient's vessel.